Adapt fmod_postfix for new config

plugins/functions/fmod_postfix.py

@@ -28,7 +28,7 @@ class Postfix(service.FunctionObject) :
 	def regenerateMainCf(self, config_filename, templates_dir):
 		with open(config_filename, 'r') as postfix_config:
 			config = safe_load(postfix_config.read())
-		template_filename = path.join(templates_dir, config['template'] + '.tpl')
+		template_filename = path.join(templates_dir, config['main-cf_template'] + '.tpl')
 		with open(template_filename, 'r') as template_text:
 			template = Template(template_text.read())